This invention relates generally to an operating mechanism for rolling doors and the like and more particularly to novel driving mechanisms permitting the safe operation of the door in either the manual drive or motor drive mode.
A rolling door structure consists of an articulated curtain arranged to be raised and lowered to open or close a doorway, window or other opening in a building. In new building construction especially, the rolling doors may be installed before the electric power is made available for driving the door using the motor operator. Consequently there is a need for a manual drive mechanism for operating the door independently of whether electric power is available to drive the motor operator. For example, periodic servicing of the motor operator may require that the door be manually operated and on those occasions of electrical power outtage, including those during or following a fire, make a manually operated door a valuable feature.
To ensure that the mechanism for manually operating the door will stand idle during motor operation of the door, it is important that there be a provision for disengaging the manual drive operator from the motor drive operator when the motor drive is needed. An efficient arrangement for manually operating a rolling door mechanism is to couple the manual drive with the motor drive and thus it is highly desirable to be able to selectively engage and disengage the manual drive from the motor drive as the need arises.
Rolling doors may be constructed as exemplified by U.S. Pat. No. 2,820,516 and include operating mechanisms as exemplified by U.S. Pat. Nos. 3,637,004, 3,853,167 and 2,934,139, all owned by the present assignee.